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Your search keyword '"Liendo, Jacinto A."' showing total 8 results
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8 results on '"Liendo, Jacinto A."'

7. Un método híbrido (dinámica molecular / MonteCarlo) para modelar plasticidades sinápticas en células excitables.

Author

Magjarevic, R., Nagel, J. H., Müller-Karger, Carmen, Wong, Sara, La Cruz, Alexandra, Macías, Alfredo, Liendo, Jacinto, and Silva, Ricardo

Abstract

Present work comprises a computational model to reproduce the dynamics of synaptic vesicles. An algorithm is developed and implemented to allow the study of synaptic plasticity resulting from the controlled fusion of synaptic vesicles in the presynaptic terminal. The presynaptic terminal is spatially modeled as a box located within the coordinate axis with the presynaptic membrane corresponding to the z=0 plane. Forces controlling changes of speed and position for each vesicle result from three sources: (1) Electric Fields originating from intracellular, extracellular and intravesicular medium [1] and from charges in the vesicular and presynaptic membranes. (2) Forces derived from the polarized water clathrate surrounding the synaptic vesicles. (3) Frictional forces derived from moving synaptic vesicles which are proportional to their speed [2]. Physical constants employed in the simulations were approximated to those reported for squid giant axon by other researchers. The size of the Synaptic Vesicles and the Terminal Box were also chosen from those reported by other researchers. Synaptic vesicles were incorporated into the terminal box by means of a predetermined sequence up to the point were the pool reached equilibrium. Once in equilibrium vesicular fusion probability was modulated to simulate periodic stimulation and response of the Synaptic Pool. Results obtain from the simulation are consistent with experimental results reported by other researchers, there fore validating the model. [ABSTRACT FROM AUTHOR]

Published
2008
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8. An electrostatic and probabilistic simulation model to describe neurosecretion at the synaptic scale.

Author

Macias-Medri AE, Liendo JA, and Silva RJ

Subjects
Animals, Exocytosis physiology, Monte Carlo Method, Models, Statistical, Neurosecretion physiology, Static Electricity, Synaptic Vesicles physiology
Abstract

A hybrid simulation model (macro-molecular dynamics and Monte Carlo method) is proposed to reproduce neurosecretion and exocytosis. A theory has been developed for vesicular dynamics based on quasi-static electric interactions and a simple transition-state model for the vesicular fusion. Under the non-equilibrium electric conditions in an electrolytic fluid, it is considered that the motion of each synaptic vesicle is influenced by electrostatic forces exerted by the membranes of the synaptic bouton, other vesicles, the intracellular and intravesicular fluids, and external elements to the neuron. In addition, friction between each vesicle and its surrounding intracellular fluid is included in the theory, resulting in a drift type movement. To validate the vesicle equations of motion, a molecular dynamics method has been implemented, where the synaptic pool was replaced by a straight angle parallelepiped, the vesicles were represented by spheres and the fusion between each vesicle and the presynaptic membrane was simulated by a Monte Carlo type probabilistic change of state. Density profiles showing clusters of preferential activity as well as fusion distributions similar to the Poisson distributions associated with miniature end-plate potentials were obtained in the simulations.

Published
2017
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